Blowoff cock



Patented Apr. 27, 1943 BLOWOFF COCK Herbert J. lvIcGrath, Bloomington, and John M. Lammedee, Chicago, 111., assignors to Wilson Engineering Corporation, Chicago, 111., a corporation of Delaware Application June 13, 1941, Serial No. 397,932

2 Claims.

This invention relates to blow-ofi cocks particularly, although not exclusively, adapted for use on locomotive boilers for the purpose of discharging from such boilers a portion of the boiler water laden with concentrates, together with sludge and sediment which accumulate in a boiler.

It has been the practice for many years to equip locomotive boilers with blow-off cocks designed to be operated by the engineer at intervals for blow-off purposes through manual manipulation of the valve. Power operated blow-01f cocks adapted to be operated by steam or air pressure have also been used to a considerable extent.

One of the purposes of our present invention is to provide a blow-off cock adapted to be intermittently operated by the engineer either by means of a power operated device requiring only the simple manipulation of a control Valve or valves for its operation, or by means of a manually operable device.

One of the difficulties encountered in blow-oil cocks as heretofore constructed has been the tendency of steam and contaminated boiler water and sludge to leak past the valve stem. Packing has been employed to prevent such leakage, but the use of packing presents vexatious problems in operation and maintenance.

Another purpose of our present invention is to eliminate the necessity of packing the valve stem by employing a closed grease chamber adapted to be compactly filled with heavy grease under pressure into which the stem projects, which will preclude leakage past the valve stem and at the same time maintain the piston rod in a thoroughly lubricated condition so as to facilitate its movements and obviate the possibility of sticking.

Some modern boilers, in addition to being equipped with an intermittently power or hand operated blow-off cock, have been also equipped with an independent provision for limited continuous blow-off. Such continuous blow-off provides for a small continuous discharge of water from the boiler, thereby eliminating or reducing the frequency of necessary operation of the intermittent blow-off cock. Our present invention aims to afiord in a single unitary structure provision for power and manually operable intermittent blow-off and provision for continuous blow-01f, both blow-oifs being discharged from the boiler through a common blow-off passage.

Another feature of our invention is a control valve for the continuous blow-off which is adapted to be controlled by steam pressure associated with the engine cylinders or with the delivery pressure of the feed water pump, so that blow-01f will be effected while the engine is operating or while the pump is delivering water.

The continuous blow-off discharge is delivered in a small stream under high pressure into a muffler or discharge pipe through which the intermittent blow-off is also discharged. The abrasive action of this jet or small high pressure stream is sufficient to cause, within a relatively short time, a deterioration of the discharge passage wall against which'it is delivered. To obviate the destructive effect of this jet on the wall, we have provided an impact element against which the jet delivers, which element is removable and readily replaceable with a new element at small cost when the wear has become sufficient to necessitate renewal,

Other features and advantages of our invention will be appreciated from the following more detailed description when considered in connection with the accompanying drawing.

Referring to the drawing:

Fig. 1 is a plan view of our improved blow-off cock;

Fig. 2 is a longitudinal sectional View taken on the line 2-2 of Fig. 1; and I Fig. 3 is a transverse sectional view on the line 33 of Fig. 1.

Referring to the drawing more in detail, reference character 5 indicates the main body of the blow-01f cock provided with a lateral extension 6 terminating in an enlarged flange 1 adapted for connection by bolts or otherwise to the shell 8 of the boiler, so that the passage 9 extending through the extension 6 is in constant communication with the interior of the boiler.

Blow-off water emerging from the boiler through the passage 9 may be discharged through the intermittent blow-01f passage ll into a discharge conduit I 2 usually branched to deliver the steam upwardly to a muffler and the water downwardly to a delivery point, or it may be discharged through the continuous blow-off passage I3 provided in the plug I4 forming the end of the body 5. From the passage l3 the continuous blow-oiT is delivered into the conduit [2 through suitable piping [5, in which is interposed a shut-off cock 16. Since the abrasive effect of the relatively small but high pressure stream delivered through the continuous blow-off passage l3 and piping 15 into the conduit 12 is sufiicient to cause rapid deterioration of the wall of the conduit l2 against which the discharge impacts, we have provided in alignment with the discharge an impact element 11 in the form of a plug, preferably of cast metal, Which can be readily replaced When necessary with very little expense. This plug is removably threaded into a boss l8 projecting laterally from the conduit l2, as illustrated in Fig. 2.

The continuous blow-oil is controlled by a valve l3 adapted to close against a seat 2| to shut off the continuous blow-off under certain conditions. The stem 22 of the valve is equipped at its outer end with a head or disc 23 disposed in a pressure chamber 24 which is in communication through a pipe 25 with a source of steam under pressure. Preferably the pipe 25 is connected with the steam supply to the engine cylinders or, if preferred, to the steam line to or from the feed water pump, so that steam pressure is admitted through pipe 25 to chamber 24 only when the engine is in operation or the pump is supplying water to the boiler, as the case may be. In either event, the steam pres- 1 sure exerted upon the disc head 23 forces the head against its seat, as illustrated in Fig. 2, thereby opening the valve l9 to permit a continuous blow-off from the boiler so long as the steam pressure holds the valve IS in open position. When the steam pressure is discontinued by shutting oii the engine or the feed water pump, the valve I9 is immediately closed by the pressure of the blow-off water to thereby discontinue the blowing off operation. A shut-off cook 26 is interposed in the pipe 25 to prevent the admission of steam pressure to the chamber 24 in the event that continuous blow-01f is not desired.

A valve seat 21 is interposed between the intermittent blow-off passage I l and the passage 9 against which a valve 28 is adapted to close to shut off blowing off through the passage II. This valve is carried by a stem 29 mounted for reciprocatory movement in a guide sleeve 3| positioned in the valve body. The stem projects beyond the end of the body 5 into a grease chamber 32 formed by a housing 33 projecting from the end of the body 5 and secured thereto in any suitable manner, such, for instance, as by a split ring clamp 34 of well known construction.

The grease chamber is equipped in a convenient location with a nipple 35 of the type commonly known as an Alemite fitting, to which may be detachably connected a pressure grease gun for compactly filling the chamber 32 with heavy grease under pressure. To prevent the chamber from becoming air bound during the filling, it

J is provided in a convenient location with an air relief cook 36.

Means for manually operating the intermittent bloW-ofi valve 28 is carried by the housing 33 and comprises a shaft 31 having an enlarged bearing portion 38 journaled in a housing cap 39. To prevent leakage along the shaft, packing 4| is interposed between the end of the wall of the cap and the enlarged bearing portion 38, and this enlarged portion is forced against the packing to compress it around the shaft by means of a screw 42 threaded through the housing wall against the opposed end of the shaft. A look nut 4-3 serves to lock the screw 42 in adjusted position. The inner portion of the shaft 31 is squared to receive a bifurcated lever 44 which straddles a reduced portion of the stem 29, so as to impart reciprocatory movement to said stem when rotative movement is imparted to the shaft. Upon the end of the shaft projecting outside the housing there is mounted a lever 45 which may be suitably linked to a lever in the engine cab by which the engineer may manipulate shaft 31 to open and close the valve 28. In this manner the intermittent blow-off valve may be manually operated by the engineer whenever occasion requires.

In our device provision is also made for power operation of the intermittent blow-off valve. For this purpose an annular portion of the casing 33 is threaded as indicated at 43 to receive the tapped open end of a power cylinder 41 which when mounted on the casing 33 is coaxially aligned with the valve stem 21'. A power piston 48 snugly fitting the cylinder is arranged to be reciprocated therein by fluid pressure. A connection 49 at one side of the piston is adapted to communicate with a source of pressure, usually compressed air although steam may be employed, and another connection 5| communicating with the cylinder at the opposite side of piston 48 is likewise adapted for communication with a source of pressure. Suitable valves (not shown) control the admission to and discharge from the cylinder of the actuating fluid, so as to move the piston in the desired direction.

The piston 48 is mounted on a stem 52 which rojects through a bore in the end Wall of casing 33 and is connected at 53 with the end of the valve 29, so that the stem and the piston rod move as a unit. Suitable packing 54 surrounding the rod serves to preclude the leakage of heavy grease, with which the chamber 32 is packed, along the rod and into the cylinder. The piston is normally biased into position to close the valve 28 against its seat, by an expansion spring 55.

From the foregoing it will be manifest that we have provided a blow-ofi cock afiording provision for both intermittent blow-oi? and continuous blow-oil". The continuous blow-off is controlled by steam or other pressure, so that blow-oil is permitted only under certain conditions, and the intermittent blow-off may be operated either by power or by hand, as desired. Furthermore, the injurious effects upon the discharge conduit of the continuous blow-off jet are nullified by a readily removable impact plug, which may be renewed when required at very slight expense.

While we have shown and described a blowoff cock of preferred practical construction, it should be manifest that the structural details disclosed are illustrative merely and may be varied within considerable limits without departing from the scope of the invention as defined in the following claims.

We claim:

1. A locomotive blow-cit cock providing for a continuous small volume blow-off and an intermittent large volume blow-off from a single connection to the interior of a boiler shell, comprising an elongated body having a plurality of chamhere, a connection extending laterally from the body for establishing communication between one of said chambers and the interior of the boiler, a discharge passage extending laterally from the other chamber, a seat between said chambers, 'a

manually controlled valve disposed in said first chamber and arranged to close against said seat, a stem for said valve extending longitudinally of the body through said other chamber, a plug threaded into the end of the body and forming one wall or said first chamber, said plug being provided with a discharge passage communicating with said chamber, a pressure controlled valve disposed in said first chamber, a pressure actue ated piston connected to operate said last mentioned valve for opening said plug passage, and a connection between said plug passage and said first mentioned discharge passage, said first mentioned discharge passage serving as the conduit for the discharge for products blown off past both of said valves.

2. A locomotive blow-off cock providing for a continuous small volume blow ofi and an intermittent large volume blow-off from a single connection to the interior of a boiler shell, comprising an elongated body provided with a plurality of chambers connected by a port, an inlet passage to one of said chambers adapted to be connected with the interior of a boiler shell, an intermittent blow-off valve positioned in said one chamber and adapted to close said port, a valve stem extending longitudinally of the body through the other chamber, means for actuating said stem to open said valve, a discharge passage extending laterally from the other chamber, a continuous blow-off valve located in said one chamber, a stem extending longitudinally of said elongated body, upon which said continuous blow-off valve is mounted, a pressure actuated piston for opening said continuous blow-oil valve, a passage controlled by said continuous blow-off valve connected to discharge into said first named discharge passage transversely thereof, and a removable plug threaded into the side wall of said first discharge passage in alignment with the discharge end of the continuous blow-off discharge passage in position to receive the impact of the discharge from said continuous Passage.

HERBERT J. MCGRATH. JOHN M. LAMMEDEE. 

